1. Field of the Invention
The invention relates to a pixel structure and a manufacturing method thereof, and more particularly relates to a pixel structure and a manufacturing method thereof using a half-tone mask manufacturing process.
2. Description of Related Art
Nowadays, multimedia technology has been well developed, which mostly benefits from an advancement of semiconductor devices and display apparatuses. As for displays, thin film transistor liquid crystal displays (TFT-LCD) with superior features such as high definition, good space utilization, low power consumption and no radiation have gradually become the mainstream of the market. In general, a TFT-LCD is mainly assembled through a thin film transistor array substrate, a color filter substrate, and a liquid crystal layer sandwiched between the two substrates.
Conventional thin film transistor array substrates include a plurality of scan lines, a plurality of data lines, and a plurality of pixel structures. In detail, each pixel structure includes a thin film transistor and a pixel electrode. The thin film transistor includes a gate electrode electrically connected to the scan line, a channel layer located on the gate electrode, and a source electrode and a drain electrode located on the channel layer. The source electrode is electrically connected to the data lines. The pixel electrode is electrically connected to the drain electrode.
In conventional technology, when manufacturing the pixel structure, the layers deposited on the substrate must be patterned, respectively, in order to form the required components. In further detail, conventional pixel structures are mostly formed through the sequential patterning of a first metal layer, a first insulating layer, a semiconductor layer, a second metal layer, a second insulating layer, and a transparent conductive layer. Specifically, after the first metal layer is patterned, the scan line and the gate electrode are formed. After the semiconductor layer is patterned, the channel layer is formed. After the second metal layer is patterned, the data line and the drain electrode and the source electrode covering the two opposite sides of the channel layer are formed. After the second metal layer is patterned, the second insulating layer is formed above the data line, the drain electrode, and the source electrode. Next, the second insulating layer is patterned to form a contact window. The contact window passes through the second insulating layer and exposes the drain electrode of the thin film transistor. Next, the transparent conductive layer is formed on the second insulating layer. Finally, the transparent conductive layer is patterned to form a pixel electrode pattern. The pixel electrode pattern is electrically connected to the drain electrode of the thin film transistor through the contact window.
Since the layers (i.e. the first metal layer, the semiconductor layer, the second metal layer, the second insulating layer, and the transparent conductive layer) must be respectively patterned, the manufacture of conventional pixel structures uses multiple mask processes. However, each mask process requires time and cost. Therefore, when considering time and cost, how to reduce the use of masks in a problem researchers are trying to solve.